The nation’s wireless carriers still have yet to see steady shipments of Apple’s cellular-enabled Retina iPad Mini, with three of the top four mobile carriers all backordered for several weeks as the holiday shopping season draws closer. According to a recent report from CNET, Verizon, AT&T and T-Mobile are all seeing estimated ship dates slip to at least December, though Apple’s own supply for Wi-Fi + Cellular iPad minis continues to improve.

The shortage suggests supplies are still constrained for the cellular 4G version of Apple’s high-resolution 7.9-inch tablet, as Verizon recently pushed back shipping estimates to December 2. The nation’s largest carrier was previously quoting a target date of November 25 but a spokesperson is now unable to say when the device will hit store shelves. As far as AT&T goes, the company’s website says all models of the Retina iPad Mini will ship in 21 to 28 business days with T-Mobile also being back-ordered for an estimated 6 to 8 weeks.

Although the carriers may not be getting adequate supply of the hot-selling mini, Apple has been bolstering its stock for customers, who now have to wait 5 to 10 days for the unit to ship. This appears to be a major improvement from launch day, when even the first orders showed wait times of a few days. At the time, the Wi-Fi + Cellular models showed 5 to 10 day ship by times, which later fell to weeks.

In a recent note to investors, KGI analyst Ming-Chi Kuo said Apple’s manufacturers will reach mass production levels early next years, with shipments expected to grow 102% over the next quarter. Those of you who are still looking to get your hands on a Retina iPad Mini as soon as possible should check out Seaturtle.org’s unofficial iPad Mini notifier, which offers a snapshot of Apple retail store availability for in-store pickup.